For preventing vehicle accidents in the event that the correct lane is going to be departed, DE 10 2005 003 177 A1 discusses a method/system to generate a counter-steering torque in the vehicle's steering system which counteracts the steering angle imposed by the driver. Such lane keeping systems (lane keeping assist) are aimed at keeping the vehicle in the predefined lane or returning it into the lane for preventing accidents. A precondition for this is a complex sensor system which permanently monitors the instantaneous vehicle position with regard to the lane and, in the event of an inadmissible departure from the setpoint trajectory, generates an appropriate counter-steering torque.
According to a vehicle steering system from DE 195 06 364 C2, the instantaneous vehicle position is determined with the aid of a navigation device, and the driving speed is corrected by automatic braking, and the vehicle position is corrected by automatic setting of the steering torque or the steering angle, so that the vehicle is able to drive safely through a curve.
Such lane keeping systems are characterized by an additional, driver-independent intervention in the vehicle state in order to keep it in the lane contrary to the driver input. However, it must be taken into account that in certain driving situations a lane departure may be intentional, e.g., to avoid an obstacle in the lane. Furthermore, quickly and reliably operating vehicle and surroundings sensor systems must be provided for safe functioning of the lane keeping system which involves considerable technical and financial expenditures.